Dalian marine parts and components gear is a kind of mechanical element with gears on the rim to continuously mesh and transmit motion and power. The application of gears in transmission appeared very early. At the end of the 19th century, the principle of generating gear cutting method and the emergence of special machine tools and cutting tools using this principle. With the development of production, the stability of gear operation has been paid attention to.

Gears can be classified according to tooth shape, gear shape, tooth line shape, tooth surface and manufacturing method.

The tooth profile of gear includes tooth profile curve, pressure angle, tooth height and displacement. Involute gears are relatively easy to manufacture, so involute gears account for the absolute majority of modern gears, while cycloid gears and circular arc gears are rarely used.

In the aspect of pressure angle, the bearing capacity of small pressure angle gear is small; The high pressure angle gear, although with high bearing capacity, increases the load of the bearing when the transmission torque is the same, so it is only used in special cases. The gear tooth height has been standardized, and the standard tooth height is generally adopted. The modified gear has many advantages and has been widely used in all kinds of mechanical equipment.

In addition, gears can also be divided into cylindrical gears, bevel gears, non-circular gears, racks, worms and worm gears according to their shapes; According to the shape of tooth line, it can be divided into spur gear, helical gear, herringbone gear and curved gear; It is divided into external gear and internal gear according to the surface of the gear teeth; According to the manufacturing method, it can be divided into cast gear, cut gear, rolled gear, sintered gear, etc.